The German education ministry has binned new computers infected by the infamous Conficker worm - and bought replacements - rather than attempting to disinfect the machines.

It emerged this week that a grand total of 170 PCs and servers at German teacher training institutes in Schwerin, Rostock and Greifswald were dumped soon after they became infected with the notorious Windows worm in September 2010. The decision cost German taxpayers €187,300 (£158,291).

Simply cleaning up the malware would have cost €130,000 (£110,000), Heise reports, reflecting a cost difference of €57,000 (just over £48k). The bill, which also included data restoration costs, only emerged through a recently published audit report.

More details on the outbreak and its aftermath are revealed on page 154 of a report [PDF, German] by auditors at the State of Mecklenburg-Vorpommern, which reports that the teacher training colleges had left themselves wide open to attack by failing to create a up-to-date security policy.

Auditors were unable to apportion blame for the spread of the Conficker worm. "It remains unclear if the anti-virus product had some issues, or if the outbreak was caused by technical or human failure," the auditors concluded, according to a translation of their report sourced by Sophos.

A blog post by the security software firm concludes that a combination of basic antivirus scanners (which might even be available at low or no charge to educational institutes) and backup software ought to have been enough to thwart the well-known threat.

That's as may be, but it's worth noting that Conficker has caused all sorts of problems at many organisations worldwide.

Conficker (AKA Downadup) first appeared in November 2008, using a then-recently patched vulnerability in Windows Server Service to wiggle its way into insecure systems. The malware also spread via infected USB sticks, which became its main route of infection as time passed.

It was the worm's aggressive scanning routines that caused the greatest headache rather than any other action it performed on infected machines. Hosts networks of infected PCs became swamped with bandwidth-sucking traffic and clean-up was far from straightforward. Early victims included the Houses of Parliament and the UK's Ministry of Defence.

Months later, secondary infections began cropping up in a variety of hospitals. Infection of the network of Greater Manchester Police prompted the force to take the unprecedented step of suspending access to the police national computer, as a precaution against the further spread of the worm, for several days back in February 2010.

The peak zombie headcount created by the botnet peaked at over six million PCs, more than enough to create all sorts of mayhem. Backdoored PCs were, of course, wide open to secondary infection but not much malfeasance along these lines actually took place.

Windows PCs infected with the C variant of Conficker were programmed to download Spyware Protect 2009 (a scareware package) and the Waledac botnet client, malware that turned zombie drones into conduits for spamming.

The spread of the worm prompted Microsoft to team up with allies in the field of information security including Trend Micro, Sophos and VeriSign to form the Conficker Working Group. The group succeeded in neutralising domains programmed to act as control hubs for the infamous worm.

still causing headachesseems a bit steep to me the cost to clean that isbut I too, would go with replacement once I got that price back